1. Field of the Invention
The present invention, in general, relates to apparatus used to prevent movement of pipes placed above the ground and, more particularly, to devices that prevent gated irrigation pipe from axially rotating.
The use of gated irrigation pipe for controlling the dispersing of irrigation water is well known. Gated irrigation pipe is available in various diameters, various lengths, and is constructed of various types of materials of which aluminum and PVC (poly-vinyl-chloride) are among the most common.
The most common way in which the sections of gated irrigation pipe are joined together is by having a smaller end of each pipe (or pipe fitting) slide into another larger bell-shaped end that is located on the side opposite of each section of pipe that the smaller end is located. Many other types of clamping arrangements that are also known are useful for joining sections of gated pipe together or for joining sections of gated pipe to pipe fittings.
All forms of gated irrigation pipe are in general placed on top of the ground surface and include gates that are located at spaced apart intervals along each section of pipe. Each of the gates are opened as desired, either fully or proportionately, to regulate the flow of irrigation water therefrom or certain of the gates are closed to prevent the flow of water therefrom.
The gates are disposed generally in a row along the longitudinal length of each section of pipe. The row of gates is then positioned at a predetermined height above the ground surface according to the demands and the preferences of each particular situation.
For example, it is not usually desirable to orient the row of gates so that it faces generally down towards the ground surface because this promotes rapid erosion of the soil in proximity to each gate by the force of the water leaving the gates. Therefore the rows of gates are normally positioned either parallel with the ground surface or slightly above or slightly below parallel depending upon factors such as the quantity of water that is desired to flow through each gate, the water pressure (or "head of water" as it is more commonly referred to), and the general soil composition in the area.
The proper attitude for each row of gates on each section of pipe is unique for each application of gated irrigation pipe. However, once a line of gated irrigation pipe is properly installed, it is desirable to maintain the gates in same orientation with respect to the ground surface.
However as the sun strikes the section of pipe they expand. When they cool at night or as clouds pass overhead, they contract. The resultant increase and decrease in the longitudinal length of each section of gated pipe is generally not significant nor is it detrimental. However, the repeated cycles of expansion and contraction cause certain of the sections of gated irrigation pipe to rotate axially thereby displacing the rows of gates away from the predetermined and desired position that they had immediately following installation.
Accordingly there exists today a need for an anti-rotation clamp for gated irrigation pipe that prevents the sections of gated irrigation pipe from rotating axially when the pipes are placed upon the ground surface.
2. Description of Prior Art
Pipe clamps are, in general, known. Anti-rotational types of pipe clamps for use with gated irrigation pipe are not generally known. For example, the following patents describe various types of pipe clamps:
U.S. Pat. No. 3,568,455 to McLaughlin et al, that issued Mar. 9, 1971; PA1 U.S. Pat. No. 3,609,932 to Di Pirro, Oct. 5, 1971; PA1 U.S. Pat. No. 3,700,197 to Branton, Oct. 24, 1972; PA1 U.S. Pat. No. 3,964,707 to Lewis, Jun. 22, 1976; PA1 U.S. Pat. No. 3,966,154 to Perrault et al, Jun. 29, 1976; PA1 U.S. Pat. No. 4,389,034 to Suttles, Jun. 21, 1983; PA1 U.S. Pat. No. 4,445,656 to Leitch et al, May 1, 1984; PA1 U.S. Pat. No. 5,007,768 to Waller, Apr. 16, 1991; PA1 U.S. Pat. No. 5,042,958 to Stenersen, Aug. 27, 1991; PA1 U.S. Pat. No. 5,156,491 to Russell, Oct. 20, 1992.
While the structural arrangements of the above described devices, at first appearance, have similarities with the present invention, they differ in material respects. These differences, which will be described in more detail hereinafter, are essential for the effective use of the invention and which admit of the advantages that are not available with the prior devices.